Question

我正在asp.net上建立一个网站。在我的页面中，我有一个日历，用户可以选择连接到SQL Server数据库的已执行手术的日期。我想展示两个不同的消息：

如果在所选日期进行了手术，它将显示GridView。我想要显示一条消息，说“＆＃34; Surgeries Performed＆＃34;。

如果在选定日期没有进行任何手术，我想要一个标签说＆＃34;没有进行手术＆＃34;

protected void Page_Load(object sender, EventArgs e)
{
    GridView1.DataSourceID = "";
    GridView1.DataSource = SqlDataSource1;
    GridView1.DataBind();
    GridView1.Visible = true;
    SurgeonsLabel.Visible = false;
    NursesLabel.Visible = false;

    if (GridView1.Rows.Count == 0)
    {
        UnscheduledSurgery.Text = "No Surgeries had been performed on the selected date. Please select other date.";
    }
    else
    {
        UnscheduledSurgery.Text = "Surgeries performed on the selected date: ";
    }
}

我无法找到可以为此工作制作代码的事件。我无法在页面加载时执行此操作，因为它始终显示某些内容，而且我无法使其在Calendar_Selected上运行，因为GridView1尚未更新（因此首先显示第一条消息）。我应该使用哪个活动？

Answer 1

试试这个

protected void Page_Load(object sender, EventArgs e)
{
    if(!Page.IsPostBack)
{
    GridView1.DataSource = SqlDataSource1;
    GridView1.DataBind();
    GridView1.Visible = true;
    SurgeonsLabel.Visible = false;
    NursesLabel.Visible = false;

    if (GridView1.Rows.Count == 0)
    {
        UnscheduledSurgery.Text = "No Surgeries had been performed on the selected date. Please select other date.";
    }
    else
    {
        UnscheduledSurgery.Text = "Surgeries performed on the selected date: ";
    }
}
}

Answer 2

下面是一个简化示例，演示了如何以您希望的方式使用GridView。您必须根据具体情况对其进行调整，但它说明了在没有数据时如何显示消息。我在Visual Studio中编写了这段代码，因此它已经过测试并且可以正常工作。尝试一下。

<!DOCTYPE html>

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title></title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        <asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="true">
            <EmptyDataTemplate>
                There is no data.
            </EmptyDataTemplate>
        </asp:GridView>
        <asp:Button runat="server" ID="btnShow" Text="Show" OnClick="btnShow_Click" />
        <asp:Button runat="server" ID="btnHide" Text="Hide" OnClick="btnHide_Click" />
    </div>
    </form>
</body>

背后的代码看起来像这样。

using System;
using System.Collections.Generic;
using System.Data;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

namespace WebApplication2
{
    public partial class WebForm1 : System.Web.UI.Page
    {

        protected void Page_Load(object sender, EventArgs e)
        {        
            GridView1.DataBind();
        }

        protected void btnShow_Click(object sender, EventArgs e)
        {

            var data = new Dictionary<int, string>();
            data.Add(1, "John");
            data.Add(2, "Bob");
            GridView1.DataSource = data;  
            GridView1.DataBind();
        }

        protected void btnHide_Click(object sender, EventArgs e)
        {
            GridView1.DataSource = null;
            GridView1.DataBind();
        }
    }
}

避免在日历上加载页面

2 个答案: